Handled a new 620 recently. Good fit & finish, decent lockup, but a hitchy trigger in both DA and SA. I don't know whether The Lock or the seven-shot lockwork was at fault, but I suspect it's the latter, as the new 686 Plus seven-shooter I handled also displayed the same hitchiness.
I haven't encountered this flaw on current S&W six-shooters. My new production 629 and Model 10 have The Lock, yet both have smooth, even triggers.
If this 620's action was typical of the new model, one would probably be better served by passing it up and finding a 66 or a regular, six-shot 686.